Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Award Type
Award Type [Axis]
Equity Award
Equity Award [Domain]
Stock Option
Employee Stock Option [Member]
Range [Axis]
Range [Axis]
Range [Domain]
Range [Domain]
Minimum
Minimum [Member]
Maximum
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum (percent)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum
Risk free interest rate, maximum (percent)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum
Expected dividend rate (percent)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate
Volatility rate, minimum (percent)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum
Volatility rate, maximum (percent)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum
Expected Term (in years)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term
Weighted average grant-date fair value per share (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value
Income Tax Disclosure [Abstract]
Income tax benefit
Income Tax Expense (Benefit)
Uncertain tax positions
Liability for Uncertainty in Income Taxes, Current
Statement of Financial Position [Abstract]
Stockholders' Equity:
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Blank check preferred stock, par value (in dollars per share)
Preferred Stock, Par or Stated Value Per Share
Blank check preferred stock, authorized shares
Preferred Stock, Shares Authorized
Blank check preferred stock, issued shares
Preferred Stock, Shares Issued
Blank check preferred stock, outstanding shares
Preferred Stock, Shares Outstanding
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share
Common stock, authorized shares
Common Stock, Shares Authorized
Common stock, issued shares
Common Stock, Shares, Issued
Common stock, outstanding shares
Common Stock, Shares, Outstanding
Treasury stock, shares
Treasury Stock, Shares
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deferred Revenue Arrangement, by Type [Table]
Deferred Revenue Arrangement, by Type [Table]
Type of Arrangement and Non-arrangement Transactions [Axis]
Type of Arrangement and Non-arrangement Transactions [Axis]
Arrangements and Non-arrangement Transactions [Domain]
Arrangements and Non-arrangement Transactions [Domain]
License and Collaborative Arrangement
Collaborative Arrangement [Member]
Legal Entity [Axis]
Legal Entity [Axis]
Entity [Domain]
Entity [Domain]
Merck
Merck, Sharpe and Dohme Corp [Member]
Merck, Sharpe and Dohme Corp [Member]
Genentech
Genentech Inc. [Member]
Genentech Inc.
Deferred Revenue Arrangement [Line Items]
Deferred Revenue Arrangement [Line Items]
Upfront cash payments
Revenue Recognition, Milestone Method, Revenue Recognized
Genentech potential milestones
Revenue Recogition, Milestone Method, Maximum Potential Revenue
Revenue Recogition, Milestone Method, Maximum Potential Revenue
Licensing and collaboration revenue
Licenses Revenue
Reimbursement for direct labor
License Revenue, Employee Labor
License Revenue, Employee Labor
Alliance manager
License Revenue, Manager Labor
License Revenue, Manager Labor
Participation in JRC
License Revenue, Committee Labor
License Revenue, Committee Labor
Deferred revenue
Deferred Revenue
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs
Schedule of Restructuring Reserve by Type of Cost [Table Text Block]
Authorized Increases of Common Stock under the 2009 Plan
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]
Stock Option Activity
Schedule of Stock Options Roll Forward [Table Text Block]
Assumptions Used in Black-Scholes Pricing Model for New Grants
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Restricted Stock Activity
Nonvested Restricted Stock Shares Activity [Table Text Block]
Earnings Per Share [Abstract]
Loss attributable to common stockholders
Net Income (Loss) Attributable to Parent
Basic and diluted weighted-average shares outstanding (in shares)
Weighted Average Number of Shares Outstanding, Basic and Diluted
Basic and diluted loss per share (in dollars per share)
Earnings Per Share, Basic and Diluted
Restructuring Charges
Restructuring and Related Activities Disclosure [Text Block]
Number of options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number
Options granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross
Options exercised (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period
Options forfeited (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period
Options expired (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period
Outstanding at end of period (in shares)
Weighted average exercise price
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, weighted average exercise price at beginning of period (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Granted, weighted average exercise price (in dollars per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price
Exercised, weighted average exercise price (in dollars per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price
Forfeitured, weighted average exercise price (in dollars per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price
Expired, weighted average exercise price (in dollars per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price
Outstanding, weighted average exercise price at end of period (in dollars per share)
Options exercisable at end of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number
Exercisable, weighted average exercise price (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price
Outstanding, weighted average remaining contractual term, in years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term
Exercisable, weighted average remaining contractual term, in years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term
Accounting Policies [Abstract]
Use of Estimates
Use of Estimates, Policy [Policy Text Block]
Principles of Consolidation
Consolidation, Policy [Policy Text Block]
Financial Instruments
Fair Value of Financial Instruments, Policy [Policy Text Block]
Concentration of Credit Risk
Concentration Risk, Credit Risk, Policy [Policy Text Block]
Property and equipment
Property, Plant and Equipment, Policy [Policy Text Block]
Revenue Recognition
Revenue Recognition, Policy [Policy Text Block]
Recent Accounting Pronouncements
New Accounting Pronouncements, Policy [Policy Text Block]
Net loss
Percentage reduction in force
Restructuring and Related Cost, Number of Positions Eliminated, Period Percent
Schedule of Financing Rounds
Financings [Table]
Financings [Table]
Subsequent Event Type [Axis]
Subsequent Event Type [Axis]
Subsequent Event Type [Domain]
Subsequent Event Type [Domain]
Subsequent event
Subsequent Event [Member]
Sale of Stock [Axis]
Sale of Stock [Axis]
Sale of Stock [Domain]
Sale of Stock [Domain]
IPO [Member]
IPO [Member]
Follow-on Offering
Follow-on Offering [Member]
Follow-on Offering [Member]
ATM Offering
ATM Offering [Member]
ATM Offering [Member]
Public Offering [Member]
Public Offering [Member]
Public Offering [Member]
Financings
Financings [Line Items]
[Line Items] for Financings [Table]
FInancing proceeds
Sale of Stock, Consideration Received on Transaction
Maximum available under ATM offering
MaximumAvailableUnderATMOffering
Maximum value of shares available for sale under a ATM offering.
Number of shares of common stock sold
Stock Issued During Period, Shares, New Issues
Fees and commissions
Fees and Commissions
Commissions paid
Payments for Commissions
Other costs
Payments of Stock Issuance Costs
Number of shares issued
Sale of Stock, Number of Shares Issued in Transaction
Number of license and collaboration arrangements
Collaborative Arrangement, Number of Arrangements
Collaborative Arrangement, Number of Arrangements
Range
Range
Performance Stock
Performance Shares [Member]
Restricted Stock
Restricted Stock [Member]
Performance Restricted Stock
Performance Restricted Stock [Member]
Performance Restricted Stock [Member]
Antidilutive Securities
Antidilutive Securities [Axis]
Antidilutive Securities, Name
Antidilutive Securities, Name [Domain]
Plan Name
Plan Name [Axis]
Plan Name
Plan Name [Domain]
2009 Equity Incentive Plan
2009 Equity Incentive Plan [Member]
2009 Equity Incentive Plan [Member]
2010 Employee Stock Purchase Plan
2010 Employee Stock Purchase Plan [Member]
2010 Employee Stock Purchase Plan [Member]
Number of shares authorized
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized
Number of shares remained available for issuance
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant
Increase in number of shares authorized
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized
Evergreen increase (percent)
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Authorized Stock Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Authorized Stock Maximum
Share-based compensation expense
Allocated Share-based Compensation Expense
Total compensation cost related to non-vested option awards
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options
Weighted average vesting period for non-vested option awards, in years
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition
Intrinsic value of options exercised
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value
Fair value of awards vested
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value
Granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period
Weighted average grant-date fair value per share (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value
Options exercisable at end of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period
Unrecognized compensation cost
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options
Fair value of restricted stock awards vested
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value
Statement of Stockholders' Equity [Abstract]
Stock issuance costs
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs
Income Statement [Abstract]
Grant revenue
Revenue from Grants
Total operating revenues
Revenue, Net
Operating expenses:
Operating Expenses [Abstract]
Research and development
Research and Development Expense
General and administrative
General and Administrative Expense
Total operating expenses
Operating Expenses
Loss from operations
Operating Income (Loss)
Other income and expense:
Nonoperating Income (Expense) [Abstract]
Miscellaneous income (expense)
Other Nonoperating Income (Expense)
Interest income
Investment Income, Interest
Interest expense
Interest Expense
Other income, net
Nonoperating Income (Expense)
Net loss
Basic and diluted average shares outstanding (in shares)
Subsequent Events [Abstract]
Subsequent Events
Subsequent Events [Text Block]
Statement of Cash Flows [Abstract]
Cash Flows From Operating Activities
Net Cash Provided by (Used in) Operating Activities [Abstract]
Adjustments to reconcile net loss to net cash used in operating activities:
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Share-based compensation
Share-based Compensation
Depreciation and amortization
Depreciation, Depletion and Amortization
Forgiveness of debt
Gain (Loss) on Extinguishment of Debt
Tax shortfall associated with employee stock plans
Excess Tax Benefit from Share-based Compensation, Operating Activities
Impairment of fixed assets
Asset Impairment Charges
Loss on sale of fixed assets
Gain (Loss) on Disposition of Property Plant Equipment
Changes in operating assets and liabilities:
Increase (Decrease) in Operating Capital [Abstract]
Prepaid expenses and other current assets
Increase (Decrease) in Prepaid Expense and Other Assets
Other receivables
Increase (Decrease) in Other Receivables
Accounts payable and accrued expenses
Increase (Decrease) in Accounts Payable and Accrued Liabilities
Income taxes receivable
Increase (Decrease) in Income Taxes Payable
Unearned revenue
Increase (Decrease) in Deferred Revenue
Deferred rent
Increase (Decrease) in Deferred Charges
Net cash used in operating activities
Net Cash Provided by (Used in) Operating Activities
Cash Flows From Investing Activities
Net Cash Provided by (Used in) Investing Activities [Abstract]
Maturity of certificates of deposit
Proceeds from Sale and Maturity of Held-to-maturity Securities
Purchase of equipment
Payments to Acquire Property, Plant, and Equipment
Proceeds on sale of equipment
Proceeds from Sale of Property, Plant, and Equipment
Net cash provided by investing activities
Net Cash Provided by (Used in) Investing Activities
Cash Flows From Financing Activities
Net Cash Provided by (Used in) Financing Activities [Abstract]
Issuance of common stock, net of offering costs
Proceeds from Issuance of Common Stock
Repurchase of common stock
Payments for Repurchase of Common Stock
Payments under capital lease obligations and principal payments on notes payable
Repayments of Debt and Capital Lease Obligations
Net cash provided by financing activities
Net Cash Provided by (Used in) Financing Activities
Net decrease in cash and cash equivalents
Cash and Cash Equivalents, Period Increase (Decrease)
Cash and cash equivalents at beginning of period
Cash and Cash Equivalents, at Carrying Value
Cash and cash equivalents at end of period
Supplemental disclosure of cash flows information:
Supplemental Cash Flow Information [Abstract]
Cash paid for interest
Interest Paid
Cash (refunds received) paid for taxes, net
Income Taxes Paid, Net
Noncash financing and investing activities:
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Equipment acquired by capital lease
Capital Lease Obligations Incurred
Forgiveness of debt
Notes Reduction
Basis of Presentation
Basis of Accounting [Text Block]
Schedule of Antidilutive Securities Excluded from Computation of Net Loss per Common Share
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Significant Accounting Policies
Significant Accounting Policies [Text Block]
Basic and Diluted Net Loss per Common Share
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Debt Disclosure [Abstract]
Long-Term Debt
Long-term Debt [Text Block]
Income Taxes
Income Tax Disclosure [Text Block]
Net Loss per Common Share
Earnings Per Share [Text Block]
Schedule of Restructuring Charges
Schedule of Restructuring and Related Costs [Table]
Restructuring Plan [Axis]
Restructuring Plan [Axis]
Restructuring Plan [Domain]
Restructuring Plan [Domain]
2016 Restructuring Plan
Two Thousand Sixteen Restructuring Plan [Member]
Two Thousand Sixteen Restructuring Plan [Member]
Restructuring Type
Restructuring Type [Axis]
Type of Restructuring
Type of Restructuring [Domain]
Employee Severance Cost
Employee Severance [Member]
Income Statement Location [Axis]
Income Statement Location [Axis]
Income Statement Location [Domain]
Income Statement Location [Domain]
General and Administrative Expense [Member]
General and Administrative Expense [Member]
Research and Development Expense [Member]
Research and Development Expense [Member]
Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Asset impairment charges
Tangible Asset Impairment Charges
Restructuring Reserve [Roll Forward]
Restructuring Reserve [Roll Forward]
Balance at beginning of period
Restructuring Reserve
Expensed
Restructuring Charges
Cash Payments
Payments for Restructuring
Balance at end of period
Fair Value Disclosure of notes payable and capital lease obligations
Long-term Debt and Capital Lease Obligations, Including Current Maturities
Accumulated depreciation
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment
Property, Plant and Equipment [Table]
Property, Plant and Equipment [Table]
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Domain]
Property, Plant and Equipment, Type [Domain]
Computer Equipment
Computer Equipment [Member]
Lab Equipment
Equipment [Member]
Contract Manufacturing Organization Equipment
Contract Manufacturing Organization Equipment [Member]
Contract Manufacturing Organization Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Line Items]
Useful life
Property, Plant and Equipment, Useful Life
Government contract receivable
Government Contract Receivable
Unbilled contracts receivable
Government Contract Receivable, Unbilled Amounts
Accrued expenses for subcontractor fees incurred under government contracts
Government Contract, Accrued Subcontractor Fees
Government Contract, Accrued Subcontractor Fees
Common Stock Equity Incentive Plan
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]
Authorized Shares Added
Statement [Table]
Statement [Table]
Statement, Equity Components
Equity Components [Axis]
Equity Component
Equity Component [Domain]
Common Stock
Common Stock [Member]
Additional Paid-in Capital
Additional Paid-in Capital [Member]
Treasury Stock
Treasury Stock [Member]
Accumulated Deficit
Retained Earnings [Member]
Statement [Line Items]
Statement [Line Items]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period
Stockholders' Equity Attributable to Parent
Balance at beginning of period (shares)
Share-based compensation
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition
Exercise of stock options and restricted stock vested
Stock Issued During Period, Value, Stock Options Exercised
Exercise of stock options and restricted stock vested (shares)
Sales of shares under stock purchase plan
Stock Issued During Period, Value, Employee Stock Purchase Plan
Sales of shares under stock purchase plan (shares)
Stock Issued During Period, Shares, Employee Stock Purchase Plans
Repurchase of common stock
Stock Repurchased During Period, Value
Issuance of common stock under the ATM Offering (net of offering costs of $561)
Stock Issued During Period, Value, New Issues
Issuance of common stock under the ATM Offering (net of offering costs of $561) (shares)
Repurchase of common stock (shares)
Stock Repurchased During Period, Shares
Balance at end of period
Balance at end of period (shares)
Document and Entity Information [Abstract]
Document and Entity Information [Abstract]
Entity Registrant Name
Entity Registrant Name
Entity Central Index Key
Entity Central Index Key
Current Fiscal Year End Date
Current Fiscal Year End Date
Entity Filer Category
Entity Filer Category
Document Type
Document Type
Document Period End Date
Document Period End Date
Document Fiscal Year Focus
Document Fiscal Year Focus
Document Fiscal Period Focus
Document Fiscal Period Focus
Amendment Flag
Amendment Flag
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Schedule of Long-term Debt Instruments
Schedule of Long-term Debt Instruments [Table]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]
Long-term Debt, Type [Domain]
Loans Payable
Loans Payable [Member]
Debt Instrument
Debt Instrument [Axis]
Debt Instrument, Name
Debt Instrument, Name [Domain]
City of Ames Forgivable Loan 2010
City of Ames Forgivable Loan 2010 [Member]
City of Ames Forgivable Loan 2010 [Member]
Debt Instrument
Debt Instrument [Line Items]
Original Available Balance
Debt Instrument, Face Amount
Full-time position requirement (in positions)
Debt Instrument, Covenant Required, Number of Positions Creation and Retention
Debt Instrument, Covenant Required, Number of Positions Creation and Retention
Term of lease
Lessee, Operating Lease, Term of Contract
Lease extension term
Lessee, Operating Lease, Renewal Term
Lease square feet
Debt Instrument, Covenant Required, Minimum Lease Area
Debt Instrument, Covenant Required, Minimum Lease Area
Subsequent Event [Table]
Subsequent Event [Table]
Subsequent Event [Line Items]
Subsequent Event [Line Items]
Description of Business
Nature of Operations [Text Block]
Assets
Assets [Abstract]
Current assets:
Assets, Current [Abstract]
Cash and cash equivalents
Prepaid expenses and other current assets
Prepaid Expense and Other Assets, Current
Income tax receivable
Income Taxes Receivable, Current
Other receivables
Other Receivables, Net, Current
Total current assets
Assets, Current
Property and equipment, net
Property, Plant and Equipment, Net
Total assets
Assets
Liabilities and Stockholders' Equity
Liabilities [Abstract]
Current liabilities:
Liabilities, Current [Abstract]
Accounts payable
Accounts Payable, Current
Accrued expenses
Accrued Liabilities, Current
Current portion of unearned revenue
Deferred Revenue, Current
Current portion of deferred rent
Deferred Rent Credit, Current
Current portion of notes payable and obligations under capital leases
Long-term Debt and Capital Lease Obligations, Current
Total current liabilities
Liabilities, Current
Long-term liabilities:
Liabilities, Noncurrent [Abstract]
Royalty obligation payable to Iowa Economic Development Authority
Deferred Government Grants Obligations, Noncurrent
Deferred Government Grants Obligations, Noncurrent
Notes payable and obligations under capital leases
Long-term Debt and Capital Lease Obligations
Deferred rent
Deferred Rent Credit, Noncurrent
Total long-term liabilities
Liabilities, Noncurrent
Total liabilities
Liabilities
Stockholders' equity:
Equity [Abstract]
Blank check preferred stock, $0.01 par value: Authorized shares — 5,000,000 at September 30, 2017 and December 31, 2016; issued and outstanding shares — 0 at September 30, 2017 and December 31, 2016
Preferred Stock, Value, Outstanding
Common stock, $0.01 par value: Authorized shares — 75,000,000 at September 30, 2017 and December 31, 2016; issued 31,375,528 and 29,193,718 at September 30, 2017 and December 31, 2016, respectively, and outstanding 31,319,751 and 29,163,673 at September 30, 2017 and December 31, 2016, respectively
Common Stock, Value, Outstanding
Additional paid-in capital
Additional Paid in Capital
Treasury stock, at cost: 55,777 and 30,045 shares at September 30, 2017 and December 31, 2016, respectively
Treasury Stock, Value
Accumulated deficit
Retained Earnings (Accumulated Deficit)
Total stockholders' equity
Total liabilities and stockholders' equity
Liabilities and Equity
Licensing and Research Collaboration Agreements
Collaborative Arrangement Disclosure [Text Block]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Unvested at beginning of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number
Vested (in shares)
Forfeited / cancelled (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period
Unvested at end of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant date fair value at beginning of period (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value
Vested, weighted average grant date fair value (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value
Forfeited/cancelled, weighted average grant date fair value (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value
Weighted average grant date fair value at end of period (in dollars per share)
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure
Commitments and Contingencies Disclosure [Text Block]